<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box1{
            border: 10px solid white;
            width: 100%;
            display: flex;
        }
        .box1-1{
            border: 10px solid white;
            flex: 1;
        }
        .box1-2{
            border: 10px solid white;
            flex: 1;
        }
        .box1-3{
            border: 10px solid white;
            flex: 1;
        }
        .box1-4{
            border: 10px solid white;
            flex: 1;
        }
        .box2{
            border: 10px solid white;
            height: 300px;
        }
        .box2>img{
            height: 100%;width: 100%;
        }
        .box3{
            border: 10px solid white;
            height: 20px;
            display: flex;
        }
        .box3-1{
            border: 10px solid white;
            flex: 1;
        }
        .box3-2{
            border: 10px solid white;
            flex:20;
        }
        .box3-3{
            border: 10px solid white;
            flex: 3;
        }
        .box4{
            border: 10px solid white;
            height: 500;
            display: flex;
        }
        .box4-1{
            border: 150px solid white;
            flex: 1;
        }
        .box4-1>img{
            height: 100%;width: 400%;
        }
        .box4-2{
            border: 150px solid white;
            flex: 1;
        }
        .box4-2>img{
            height: 100%;width: 400%;
        }
        .box4-3{
            border: 150px solid white;
            flex: 1;
        }
        .box4-3>img{
            height: 100%;width: 400%;
        }
        .box4-4{
            border: 150px solid white;
            flex: 1;
        }
        .box4-4>img{
            height: 100%;width: 400%;
        }
    </style>
</head>
<body>
    <div class="box1">
        在线教学管理平台
        <div class="box1-1">
            <a href="">首页</a></div>
        <div class="box1-2">公告通知</div>
        <div class="box1-3">课程中心</div>
        <div class="box1-4">数据管理</div>
    </div>
    <div class="box2">
        <img src="11.PNG" alt="">
    </div>
    <div class="box3">
        <div class="box3-1">
            <form action="">
                 <input type="button"value="本校课程">
            </form>
        </div>
        <div class="box3-2">
            <input type="text">
        </div>
        <div class="box3-3">
            <form action="">
                <input type="button"value="登录">
            </form>
        </div>
    </div>
    <div class="box4">
        <h1>推荐课程</h1>
        <div class="box4-1">
            <img src="22.png" alt="">三维模型设计与制作</div>
        <div class="box4-2">
            <img src="33.jpg" alt=""> 网店运营实物</div>
         <div class="box4-3">
            <img src="44.jpg" alt="">Java高级特性编程及实战</div>
         <div class="box4-4">
            <img src="55.jpg" alt=""> 新媒体运营管理</div>
    </div>
</div>
</body>
</html>